1. Field of the Invention
This invention relates to methods of fabricating protective coatings for a crucible. More specifically, the invention is a method of fabricating a protective coating for a crucible where the method simultaneously creates multi-purpose channels within the coating and coupled to the crucible""s outer wall.
2. Description of the Related Art
Crucibles are used as containers in a wide variety of metallurgic and crystal growing processes owing to their ability to withstand high heats while remaining inert with respect to the chemicals contained therein. Materials typically used for crucibles include ceramics (e.g., alumina, aluminum nitride, boron nitride, etc.) quartz and glass. The downside of these materials is their brittleness thereby necessitating some sort of protection for the crucible and its contents. Further, it is frequently necessary to heat/cool the crucible, measure temperatures thereon, or otherwise attach some sort of sensing mechanism thereto. Once again, this requires some sort of special set-up for each operation.
Accordingly, it is an object of the present invention to provide a method of fabricating a protective wall for a crucible while simultaneously providing the means to accommodate a variety of systems/processes requiring access to a portion of the crucible""s outer wall.
Another object of the present invention is to provide a protective coating for a crucible with one or more channels being defined in the coating adjacent the crucible""s outer wall.
Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.
In accordance with the present invention, a method of fabricating a protective coating for a crucible is provided where the coating has channels formed therein. The crucible is generally made from a material having a high melting temperature on the order of 1500xc2x0 C. or greater. A material is adhered to the outer wall of the crucible to form a pattern thereon. This material should have a temperature of transformation that is less than the melting temperature of the crucible""s material. The outer wall of the crucible along with the pattern of material adhered thereto is next coated with another material such that the crucible""s outer wall along with the pattern of material adhered thereto are substantially covered. The material used to form the pattern should extend through the outer material coating to define at least one port therein. The outer material coating should have a melting temperature that is greater than the temperature of transformation of pattern of material adhered to the outer wall of the crucible. Next, the crucible with its pattern of material and outer coating material is heated to at least the temperature of transformation. Such transformation could also be accomplished by using a solvent that causes the pattern of material to dissolve. In either case, the pattern of material is transformed to a fluidic state. Finally, the material in its fluidic state is removed via the at least one port formed in the outer material coating thereby leaving channels defined in the coating adjacent the outer wall of the crucible. The outer coating material serves to protect the crucible while the resultant channels can be used for a variety of purposes.